A known structure for using a single image pickup element to capture a pair of images having parallax for displaying a stereoscopic image is to provide a left/right pair of light-receiving elements for each microlens in a two-dimensional array of lenses and to construct a left-eye captured image from the pixel signal obtained with the left-eye light-receiving element and a right-eye captured image from the pixel signal obtained with the right-eye light-receiving element. Examples of such image pickup elements are disclosed in JP 2011-515045 A (PTL 1) and JP 2003-523646 A (PTL 2).